The present invention relates to diaphragm valves, such as are used as shut-off valves, as well as flow-responsive or pressure-responsive regulator valves.
A large number of shut-off or regulator valves have been developed. One type, commonly called the globe-type because of the global shape of its housing, typically includes a valve member movable by a stem, and/or the pressure in a control chamber, towards or away from the valve seat. Such a valve generally involves an abrupt change in the direction of the flow when passing through it, and is therefore usually characterized by relatively high pressure drops, turbulence, and other poor flow characteristics. Another type of known valve, commonly called the Y-pattern type, produces less of a change in the flow direction, and therefore has better flow characteristics, but is more difficult to manufacture. In addition, both of the above types of valves generally produce a high degree of "chatter" during the closing of the valve.